In recent years, various models of semiconductor power converters are offered to the market at relatively low costs and they are used by many users for various purposes. This increases the number of users who use semiconductor power converters in an environment in which the temperature is outside the temperature range indicated in the specification of the semiconductor power converter. Using the semiconductor power conductor in such an environment causes a decrease in lifetime and degradation of the characteristics of heat-generating components, such as semiconductor switching elements and capacitors of main circuits of the semiconductor power converters. To address these problems, a conventional technique disclosed in, e.g., Patent Literature 1 employs a structure designed to cool a heat-generating component by transferring heat generated with by loss in the heat-generating component to a radiation fin as well as cooling the heat-generating component by controlling a rotational speed of a cooling fan on the basis of a temperature value detected by a temperature sensor provided in the radiation fin.